How smart would a 'smart wall' be?

While even the strongest proponents for such a technological solution admit physical barriers are likely best in urban areas such as San Diego and El Paso, they see a virtual wall as a cheaper and more effective way to police much of the rest of the 2,000-mile southwest border.

U.S. Customs and Border Protection has asked for $223 million of its fiscal 2019 budget to focus on technology improvements, funding that could have bipartisan support.

But the increased focus on smart walls is deepening concern about a growing Big-Brother-is-watching network, and civil liberties organizations have asked lawmakers to proceed with caution.

“Warrantless use of these technologies comes at an unacceptably high cost,” Neema Singh Guliani and Michelle Fraling, officials with the American Civil Liberties Union, said last month. “They allow the government to track, surveil, and monitor individuals indiscriminately and with precise detail. Individuals in the border zone should not be subject to near-constant surveillance that intrudes on the most intimate aspects of their lives.”